code: def testEmpty(self):
      MonoWriter(filename="foo.wav")([])
      self.assertTrue(not os.path.exists("foo.wav"))
  
file_path: essentia/test/src/unittests/io/test_monowriter.py
imports: from essentia_test import *
  import sys
  from numpy import pi, sin
  import os
label_desc: Use image node_id 2 for calling the TestMonoWriter obj's underlying member method code with example usage: obj.testEmpty() without return types